The present invention relates to a washer, a fastener provided with a washer, and a method of and a power tool for fastening objects.
It is known to fasten objects with one another with power tools which use fasteners having a multi-part replacement nut, for example including an inner sleeve, an outer sleeve, and a washer. Such a replacement nut is disclosed for example in our U.S. Pat. No. 5,341,560. Another replacement nut is disclosed in our U.S. Pat. No. 6,254,323 in which a bolt has a spline underneath its upper thread, to which a washer is non-rotatably connected, and the bolt also has engaging means for applying a reaction force, while an active force of the same tool turns the nut on the bolt thread and the washer face. In the fastener disclosed in both above mentioned patents, the common features are the use of the action and reaction force of one tool, the elimination of reaction arms on power tools, the conversion of torque to torsion-free bolt stretching and obtaining for the first time the desired residual bolt load rather than a torque, which is estimated based on calculated frictions rather than on actual frictions or a tension, which is based on estimated bolt relaxation when the force is transmitted from the elongated bolt to the hand-tight nut.
One solution is disclosed in my patent application Ser. No. 10/010,377. In this patent application a washer is proposed which has a first bearing face surface located at one axial side and cooperating with a nut, a second bearing surface located at an opposite axial side and cooperating with an object, and at least one third turning resistant surface cooperating with a thread of the bolt so that when the nut is turned with a given force in one direction and a body of the washer receives a given force in an opposite direction, only the nut turns to tighten or loosen the bolt and the body of the washer remains rotation stationary, while the bolt elongates or relaxes in an axial direction. However, it can be made more manufacturing friendly to reduce its manufacturing cost.